Vehicle steering wheel

ABSTRACT

The invention relates to a vehicle steering wheel, comprising a skeleton, a gas bag module which is axially movably coupled with the skeleton in such a way that by pressing against the gas bag module a contact is closed for actuating a horn, and a resilient return element for the gas bag module. The gas bag module comprises a gas bag with an opening edge defining an inflation opening as well as comprises a flange clamping the opening edge on an inside of the gas bag for fastening the gas bag. Bearing pins are provided which directly engage the flange and which are attached to one of the skeleton and a part stationarily mounted directly to the skeleton.

TECHNICAL FIELD

[0001] This invention relates to a vehicle steering wheel comprising askeleton and a gas bag module which is axially movably coupled with theskeleton.

BACKGROUND OF THE INVENTION

[0002] Gas bag modules which for actuating the horn are movably mountedon the vehicle steering wheel are referred to as “floating horn”modules. Upon deployment, the gas bag must be firmly attached to the gasbag module in the vicinity of the opening edge, so as not to be torn outof the module by the thrust generated by the gas released. To this end,the gas bag is usually clamped between two metal sheets in the vicinityof the opening edge, a flange in the form of a metal ring being usuallyplaced on the inside of the opening edge. In the prior art, this flangeis urged against a flange of the gas generator, so that the gas bag isclamped between these two parts. The gas generator is attached to a gasgenerator mounting plate which at another point is in turn axiallymovably mounted on the skeleton or on a part attached to the skeleton.The individual parts should have a stable design so as to introduce theforces, for retaining the gas bag, into the skeleton.

BRIEF SUMMARY OF THE INVENTION

[0003] The invention creates a vehicle steering wheel which has lessweight, is more stable and is formed of less parts than vehicle steeringwheels known so far. This is achieved in a vehicle steering wheel whichcomprises a skeleton, a gas bag module which is axially movably coupledwith the skeleton in such a way that by pressing against the gas bagmodule a contact is closed for actuating a horn, and a resilient returnelement for the gas bag module. The gas bag module comprises a gas bagwith an opening edge defining an inflation opening as well as comprisesa flange clamping the opening edge on an inside of the gas bag forfastening the gas bag. Bearing pins are provided which directly engagethe flange and which are attached to one of the skeleton and a partstationarily mounted directly to the skeleton. In the vehicle steeringwheel proposed, the force exerted on the flange is preferably directlyintroduced into the skeleton and not via numerous other connectingelements and parts such as the flange of the generator, a generatormounting plate and a metal sheet on the skeleton. Due to the directintroduction of force into the skeleton or into a part directly mountedon the skeleton less mounting elements are provided than in the priorart, as the load-bearing intermediate metal sheets and their attachmentscan be omitted.

[0004] Preferably, the bearing pins are attached to the skeleton in sucha way that an axial movement of the gas bag module together with thebearing pins, for actuating the horn, is permitted. The axial mountingis thus arranged in the vicinity of the steering wheel skeleton, wheremore room is available than in the vicinity of the gas bag module.

[0005] Moreover, on at least one of the bearing pins one of the contactsto be closed may be mounted, so that the bearing pin together with thecontact forms a preassembled unit and only few parts will have to bemounted when incorporating the gas bag module in the steering wheel.

[0006] The bearing pins can also form a lateral guidance for the gas bagmodule, so that further guide surfaces become superfluous.

[0007] In accordance with a preferred embodiment, the bearing pins aredesigned as threaded pins. Nuts screwed onto the threaded pins directlyengage the skeleton or the part stationarily mounted on the skeleton. Ontheir outer surface, the nuts have a lateral guidance for the gas bagmodule.

[0008] Preferably, the skeleton or the part stationarily mounteddirectly on the skeleton has a guide sleeve in which slides the nut.

[0009] In accordance with another embodiment a latching connection isprovided by means of which said bearing pins are fixed to said skeleton.When the bearing pins are designed as threaded pins having a threadedend, a nut with an integrally formed latching nose may, for instance, bescrewed onto the bearing pins each at the threaded end.

[0010] When each bearing pin is composed of several parts, for instanceas threaded pin with a nut screwed onto the same, a gas generatorcarrier may preferably be clamped between the nut and the flange. Sincethe gas generator carrier need not absorb any load upon deployment ofthe gas bag, it may be designed as plastic part, whereby the weight ofthe vehicle steering wheel will be reduced. In this connection, oneembodiment provides that the gas generator carrier is designed aspot-shaped housing of the gas bag module.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 shows a cross-sectional view of a first embodiment of thevehicle steering wheel according to the invention,

[0012]FIG. 2 shows a cross-sectional view of a second embodiment of thesteering wheel according to the invention, and

[0013]FIG. 3 shows an enlarged view of the framed portion of FIG. 2designated with X.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014]FIG. 1 represents a vehicle steering wheel which has a steeringwheel skeleton 10, for instance of a die-cast material. In FIG. 1, onlythe skeleton portion in the vicinity of the hub 12 is represented. Onthe right-hand half, a spoke 14 and the steering-wheel rim 16 areindicated in a stylized manner. The axis A is the imaginary middle axisof the steering shaft.

[0015] A gas bag module 18 is mounted on the skeleton 10 so as to bemovable in axial direction. The gas bag module has a pot-shaped plastichousing 20, also referred to as gas generator carrier, which is closedtoward the occupant by a covering cap 22. Arranged in the housing 20 area folded gas bag 24, the upper outside geometry of which is symbolizedby broken lines, a gas generator 26 which protrudes into the interior ofthe gas bag 24, and an annular flange 28 of sheet metal. The gas bag hasan opening, referred to as inflation opening 30, through which the gasgenerator 26 extends partly into the interior of the gas bag 24. Theso-called opening edge 32 of the gas bag, which defines the inflationopening, is disposed directly below the flange 28. In the directiontoward the hub 12, and below the opening edge 32 the base part 36 of thehousing is disposed, and on its lower surface there is provided anannular flange 34 integrally molded on the generator 26.

[0016] Distributed around the periphery of the flange 28 merely threebearing pins 40 are directly and permanently attached by deforming thesebearing pins 40. The bearing pins are designed as threaded pins andextend each through an associated opening in the opening edge 32, in thebase part 36 of the housing 20 and in the annular flange 34. A nut 44has been screwed on each threaded pin from below, so that the openingedge 32, the base part 36 and the annular flange 34 are clamped betweenthe flange 28 and the nut 44. The gas bag 24 is in this way firmlyarrested at the vehicle steering wheel. At their free ends, the nuts 44have a latching nose 50 in the form of a conical end with an undercutportion 52, in which can snap a holding spring 56 directly mounted on anextension 54 of the skeleton 10. For mounting the gas bag module inaccordance with this embodiment, the same must only be pressed in fromabove, until the springs 56 snap into the undercut portions 52.

[0017] In this embodiment, the force generated upon deployment of thegas bag 24 is directly introduced into the skeleton 20 via the bearingpins 40, without further intermediate metal sheets being necessary. Thehousing 20 and the annular flange 34 are also exposed to small loadsupon deployment of the gas bag.

[0018] The gas bag module is axially movably mounted by the latchingconnection, a resilient return element 60 in the form of a helicalspring being clamped between the lower surface of the gas bag module 18and the upper surface of the skeleton 10.

[0019] When the gas-bag module is pressed downwards, two contacts 70(one at the gas bag module 18, one at the skeleton 10) get in contactwith each other, close an electrical circuit, and a horn signal can beheard. Upon actuation of the gas bag module 18, the contact can thus beclosed for actuating the horn. When the gas bag module 18 is moveddownwards in the direction of the arrow, the nuts 44 move downwards, andthe undercut portions 52 likewise move downwards without the holdingsprings 56 coming in an unlatched position. The return movement iseffected by means of the return element 60.

[0020] The embodiment as shown in FIG. 2 partly corresponds to the oneshown in FIG. 1, parts of an identical function being provided with thereference numerals already introduced.

[0021] In the embodiment as shown in FIG. 2, a fastening metal sheet 80is attached to the skeleton 10 directly and not movably with respect tothe same. In this embodiment, the gas generator 26 has no annular flange34 directly mounted on it. Rather, between the gas generator 26 and theannular flange 34 a rubber sleeve 82 is provided for uncoupling thevibrations of the gas generator 26.

[0022] In this embodiment, too, the gas bag module 18 is axially movablymounted on the skeleton 10, to be more precise on the part 80. Aplurality of bearing pins 40, of which only one is shown in FIG. 3, aredesigned as threaded pins, which are permanently fixed in the flange 28.The bearing pins 40 extend through openings in the gas bag 24, theunderlying annular flange 34 and a base part 36. The nuts 44 screwedonto the bearing pins 40 from below have a protruding head 86, whichserves as axial stop, and have a bushing-like portion with a circularcylindrical outer surface which acts as lateral guidance 88 for the gasbag module 18. A guide sleeve 90 mounted in the part 80 accommodates thenut 44. Via the bearing pins 40 and the nuts 44, the gas bag module 18is guided not only axially, but also laterally.

[0023] In this embodiment, a resilient contact 90 is mounted on thebearing pins 40, which contact is held in an elastic seat 92. To theguide sleeve 90, a counter-contact with a base portion 94 and a spring96 is attached. When the contacts 90, 96 get in contact with each otherdue to the movement of the gas bag module 18 in the direction of thearrow, the horn is actuated.

[0024] The particularity of both embodiments shown is the fact that onlyvia the bearing pins 40 individual parts inside the gas bag module 18(gas generator with annular flange 34, gas bag 24, flange 28 and gasgenerator carrier 20) are attached to each other, and the entirety ofthe gas bag module 18 is at the same time axially movably mounted on theside of the skeleton via the bearing pins 40.

[0025] It is to be noted that the guiding nut 44 according to the secondembodiment can also be used in the first embodiment where the pins beingdisplaceably mounted to the skeleton. This third embodiment wouldcorrespond to FIG. 3 by the part 80 defining the skeleton.

1. A vehicle steering wheel, comprising a skeleton, a gas bag modulewhich is axially movably coupled with said skeleton in such a way thatby pressing against said gas bag module a contact is closed foractuating a horn, and a resilient return element for said gas bagmodule, said gas bag module including a gas bag with an opening edgedefining an inflation opening as well as including a flange clampingsaid opening edge on an inside of said gas bag for fastening said gasbag, bearing pins being provided which directly engage said flange andwhich are attached to one of said skeleton and a part stationarilymounted directly to said skeleton.
 2. The vehicle steering wheel asclaimed in claim 1, wherein said bearing pins are attached to saidskeleton in such a way that an axial movement of said gas bag moduletogether with said bearing pins, for actuating said horn, is permitted.3. The vehicle steering wheel as claimed in claim 1, wherein on at leastone of said bearing pins one of said contacts to be closed is mounted.4. The vehicle steering wheel as claimed in claim 1, wherein saidbearing pins also form a lateral guidance for said gas bag module. 5.The vehicle steering wheel as claimed in claim 1, wherein said bearingpins are designed as threaded pins and wherein nuts are provided whichnuts engage one of said skeleton and said part, which part is directlyand stationarily mounted on said skeleton, and which nuts have an outersurface forming a lateral guidance for said gas bag module, said bearingpins being screwed into said nuts.
 6. The vehicle steering wheel asclaimed in claim 5, wherein said outer surface of said nut iscylindrical.
 7. The vehicle steering wheel as claimed in claim 5,wherein a guide sleeve is provided for each of said nuts, said guidesleeve being provided on one of said skeleton and said part directly andstationarily mounted on said skeleton.
 8. The vehicle steering wheel asclaimed in claim 1, wherein a latching connection is provided by meansof which said bearing pins are fixed to said skeleton.
 9. The vehiclesteering wheel as claimed in claim 8, wherein said bearing pins aredesigned as threaded pins having a threaded end onto which a nut isscrewed, said nut having an integrally molded latching nose.
 10. Thevehicle steering wheel as claimed in claim 5, wherein a gas generatorcarrier is clamped between said nut and said flange.
 11. The vehiclesteering wheel as claimed in claim 1, wherein a gas generator carriermade of plastics is provided.
 12. The vehicle steering wheel as claimedin claim 1, wherein a gas generator carrier constituting a pot-shapedhousing of said gas bag module is provided.